How to find if a video is auto-rotated? Show real auto-rotate header field?

[pxstein]

Assume I have a *.MP4 video with a resolution of 2400 x 1080 pixel or 1080 x 2040 pixel.

When I double click it the well known VLC video player on Windows plays it correctly in portrait mode.
When I load it into Avidemux video editor then its somehow shown and loaded rotated by 90 deg to the left.

How do I find out if the MP4 video file really contains a header field with a auto-rotate value of 90 deg counterclockwise?

Is there video info tool with a peek-into-video-header function?

If there is currently such a header value:
How can I auto-rotate the video (with minimum quality loss) by 90 deg clockwise and set the auto-rotate flag in header to 0 (=zero)?

[Selur]

MediaInfo works fine for mp4 and mov files.

How can I auto-rotate the video (with minimum quality loss) by 90 deg clockwise and set the auto-rotate flag in header to 0 (=zero)?

you would have to reencode. (In theory for some formats some sort of repackaging, rewriting tons of headers etc. could be done, but since the effort to do it would probably not far away from a reencode and not many people really need it I haven't seen anybody spend much time on it in the last 10-20+years. So I would say: forget it)

Cu
Selur

[Alwyn]

AVIDemux will rewrite the rotation flag with no recoding, by the looks, but you have to keep your wits about you.

Open the file. From what you see in the AVIDemux window (not VLC Player), in the MP4 Output Muxer "Configure" section, set the rotation to what you want. The file header will be re-written but the video won't be encoded and it will be rotated in VLC Player. If you open that new file in AVIDemux, no go, it seems to simply ignore all rotation flags. But your file will be rotated.

I'm wondering though, if it displays correctly in VLC Player, why you'd want to rotate it?

[Selur]

Removing the flag is no problem, how I understood it he wanted to adjust the data so that the rotation flag wouldn't be needed any more.

[aedipuss]

don't be just another apple moron. video is shot ~ 16/9. look at any tv or display. portrait mode is for STILL pictures only.

[Cornucopia]

There is LOTS of digital signage video that is designed for portait mode. I have at least 2 on my campus alone. It is valid to have video shot in portrait mode to support it, and understandable that there might be issues with compatibility and rotation support.

Scott